support for mount by label (not yet tested)
Also adds findfs applet. Closes bug 1143.
diff --git a/util-linux/volume_id/fat.c b/util-linux/volume_id/fat.c
new file mode 100644
index 0000000..4c2a917
--- /dev/null
+++ b/util-linux/volume_id/fat.c
@@ -0,0 +1,333 @@
+/*
+ * volume_id - reads filesystem label and uuid
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include "volume_id_internal.h"
+
+#define FAT12_MAX 0xff5
+#define FAT16_MAX 0xfff5
+#define FAT_ATTR_VOLUME_ID 0x08
+#define FAT_ATTR_DIR 0x10
+#define FAT_ATTR_LONG_NAME 0x0f
+#define FAT_ATTR_MASK 0x3f
+#define FAT_ENTRY_FREE 0xe5
+
+struct vfat_super_block {
+ uint8_t boot_jump[3];
+ uint8_t sysid[8];
+ uint16_t sector_size;
+ uint8_t sectors_per_cluster;
+ uint16_t reserved;
+ uint8_t fats;
+ uint16_t dir_entries;
+ uint16_t sectors;
+ uint8_t media;
+ uint16_t fat_length;
+ uint16_t secs_track;
+ uint16_t heads;
+ uint32_t hidden;
+ uint32_t total_sect;
+ union {
+ struct fat_super_block {
+ uint8_t unknown[3];
+ uint8_t serno[4];
+ uint8_t label[11];
+ uint8_t magic[8];
+ uint8_t dummy2[192];
+ uint8_t pmagic[2];
+ } __attribute__((__packed__)) fat;
+ struct fat32_super_block {
+ uint32_t fat32_length;
+ uint16_t flags;
+ uint8_t version[2];
+ uint32_t root_cluster;
+ uint16_t insfo_sector;
+ uint16_t backup_boot;
+ uint16_t reserved2[6];
+ uint8_t unknown[3];
+ uint8_t serno[4];
+ uint8_t label[11];
+ uint8_t magic[8];
+ uint8_t dummy2[164];
+ uint8_t pmagic[2];
+ } __attribute__((__packed__)) fat32;
+ } __attribute__((__packed__)) type;
+} __attribute__((__packed__));
+
+struct vfat_dir_entry {
+ uint8_t name[11];
+ uint8_t attr;
+ uint16_t time_creat;
+ uint16_t date_creat;
+ uint16_t time_acc;
+ uint16_t date_acc;
+ uint16_t cluster_high;
+ uint16_t time_write;
+ uint16_t date_write;
+ uint16_t cluster_low;
+ uint32_t size;
+} __attribute__((__packed__));
+
+static uint8_t *get_attr_volume_id(struct vfat_dir_entry *dir, unsigned count)
+{
+ unsigned i;
+
+ for (i = 0; i < count; i++) {
+ /* end marker */
+ if (dir[i].name[0] == 0x00) {
+ dbg("end of dir");
+ break;
+ }
+
+ /* empty entry */
+ if (dir[i].name[0] == FAT_ENTRY_FREE)
+ continue;
+
+ /* long name */
+ if ((dir[i].attr & FAT_ATTR_MASK) == FAT_ATTR_LONG_NAME)
+ continue;
+
+ if ((dir[i].attr & (FAT_ATTR_VOLUME_ID | FAT_ATTR_DIR)) == FAT_ATTR_VOLUME_ID) {
+ /* labels do not have file data */
+ if (dir[i].cluster_high != 0 || dir[i].cluster_low != 0)
+ continue;
+
+ dbg("found ATTR_VOLUME_ID id in root dir");
+ return dir[i].name;
+ }
+
+ dbg("skip dir entry");
+ }
+
+ return NULL;
+}
+
+int volume_id_probe_vfat(struct volume_id *id, uint64_t off)
+{
+ struct vfat_super_block *vs;
+ struct vfat_dir_entry *dir;
+ uint16_t sector_size;
+ uint16_t dir_entries;
+ uint32_t sect_count;
+ uint16_t reserved;
+ uint32_t fat_size;
+ uint32_t root_cluster;
+ uint32_t dir_size;
+ uint32_t cluster_count;
+ uint32_t fat_length;
+ uint64_t root_start;
+ uint32_t start_data_sect;
+ uint16_t root_dir_entries;
+ uint8_t *buf;
+ uint32_t buf_size;
+ uint8_t *label = NULL;
+ uint32_t next;
+ int maxloop;
+
+ dbg("probing at offset 0x%llx", (unsigned long long) off);
+
+ vs = volume_id_get_buffer(id, off, 0x200);
+ if (vs == NULL)
+ return -1;
+
+ /* believe only that's fat, don't trust the version
+ * the cluster_count will tell us
+ */
+ if (memcmp(vs->sysid, "NTFS", 4) == 0)
+ return -1;
+
+ if (memcmp(vs->type.fat32.magic, "MSWIN", 5) == 0)
+ goto valid;
+
+ if (memcmp(vs->type.fat32.magic, "FAT32 ", 8) == 0)
+ goto valid;
+
+ if (memcmp(vs->type.fat.magic, "FAT16 ", 8) == 0)
+ goto valid;
+
+ if (memcmp(vs->type.fat.magic, "MSDOS", 5) == 0)
+ goto valid;
+
+ if (memcmp(vs->type.fat.magic, "FAT12 ", 8) == 0)
+ goto valid;
+
+ /*
+ * There are old floppies out there without a magic, so we check
+ * for well known values and guess if it's a fat volume
+ */
+
+ /* boot jump address check */
+ if ((vs->boot_jump[0] != 0xeb || vs->boot_jump[2] != 0x90) &&
+ vs->boot_jump[0] != 0xe9)
+ return -1;
+
+ /* heads check */
+ if (vs->heads == 0)
+ return -1;
+
+ /* cluster size check*/
+ if (vs->sectors_per_cluster == 0 ||
+ (vs->sectors_per_cluster & (vs->sectors_per_cluster-1)))
+ return -1;
+
+ /* media check */
+ if (vs->media < 0xf8 && vs->media != 0xf0)
+ return -1;
+
+ /* fat count*/
+ if (vs->fats != 2)
+ return -1;
+
+ valid:
+ /* sector size check */
+ sector_size = le16_to_cpu(vs->sector_size);
+ if (sector_size != 0x200 && sector_size != 0x400 &&
+ sector_size != 0x800 && sector_size != 0x1000)
+ return -1;
+
+ dbg("sector_size 0x%x", sector_size);
+ dbg("sectors_per_cluster 0x%x", vs->sectors_per_cluster);
+
+ dir_entries = le16_to_cpu(vs->dir_entries);
+ reserved = le16_to_cpu(vs->reserved);
+ dbg("reserved 0x%x", reserved);
+
+ sect_count = le16_to_cpu(vs->sectors);
+ if (sect_count == 0)
+ sect_count = le32_to_cpu(vs->total_sect);
+ dbg("sect_count 0x%x", sect_count);
+
+ fat_length = le16_to_cpu(vs->fat_length);
+ if (fat_length == 0)
+ fat_length = le32_to_cpu(vs->type.fat32.fat32_length);
+ dbg("fat_length 0x%x", fat_length);
+
+ fat_size = fat_length * vs->fats;
+ dir_size = ((dir_entries * sizeof(struct vfat_dir_entry)) +
+ (sector_size-1)) / sector_size;
+ dbg("dir_size 0x%x", dir_size);
+
+ cluster_count = sect_count - (reserved + fat_size + dir_size);
+ cluster_count /= vs->sectors_per_cluster;
+ dbg("cluster_count 0x%x", cluster_count);
+
+ if (cluster_count < FAT12_MAX) {
+ strcpy(id->type_version, "FAT12");
+ } else if (cluster_count < FAT16_MAX) {
+ strcpy(id->type_version, "FAT16");
+ } else {
+ strcpy(id->type_version, "FAT32");
+ goto fat32;
+ }
+
+ /* the label may be an attribute in the root directory */
+ root_start = (reserved + fat_size) * sector_size;
+ dbg("root dir start 0x%llx", (unsigned long long) root_start);
+ root_dir_entries = le16_to_cpu(vs->dir_entries);
+ dbg("expected entries 0x%x", root_dir_entries);
+
+ buf_size = root_dir_entries * sizeof(struct vfat_dir_entry);
+ buf = volume_id_get_buffer(id, off + root_start, buf_size);
+ if (buf == NULL)
+ goto found;
+
+ dir = (struct vfat_dir_entry*) buf;
+
+ label = get_attr_volume_id(dir, root_dir_entries);
+
+ vs = volume_id_get_buffer(id, off, 0x200);
+ if (vs == NULL)
+ return -1;
+
+ if (label != NULL && memcmp(label, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, label, 11);
+ volume_id_set_label_string(id, label, 11);
+ } else if (memcmp(vs->type.fat.label, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, vs->type.fat.label, 11);
+ volume_id_set_label_string(id, vs->type.fat.label, 11);
+ }
+ volume_id_set_uuid(id, vs->type.fat.serno, UUID_DOS);
+ goto found;
+
+ fat32:
+ /* FAT32 root dir is a cluster chain like any other directory */
+ buf_size = vs->sectors_per_cluster * sector_size;
+ root_cluster = le32_to_cpu(vs->type.fat32.root_cluster);
+ dbg("root dir cluster %u", root_cluster);
+ start_data_sect = reserved + fat_size;
+
+ next = root_cluster;
+ maxloop = 100;
+ while (--maxloop) {
+ uint32_t next_sect_off;
+ uint64_t next_off;
+ uint64_t fat_entry_off;
+ int count;
+
+ dbg("next cluster %u", next);
+ next_sect_off = (next - 2) * vs->sectors_per_cluster;
+ next_off = (start_data_sect + next_sect_off) * sector_size;
+ dbg("cluster offset 0x%llx", (unsigned long long) next_off);
+
+ /* get cluster */
+ buf = volume_id_get_buffer(id, off + next_off, buf_size);
+ if (buf == NULL)
+ goto found;
+
+ dir = (struct vfat_dir_entry*) buf;
+ count = buf_size / sizeof(struct vfat_dir_entry);
+ dbg("expected entries 0x%x", count);
+
+ label = get_attr_volume_id(dir, count);
+ if (label)
+ break;
+
+ /* get FAT entry */
+ fat_entry_off = (reserved * sector_size) + (next * sizeof(uint32_t));
+ buf = volume_id_get_buffer(id, off + fat_entry_off, buf_size);
+ if (buf == NULL)
+ goto found;
+
+ /* set next cluster */
+ next = le32_to_cpu(*((uint32_t *) buf) & 0x0fffffff);
+ if (next == 0)
+ break;
+ }
+ if (maxloop == 0)
+ dbg("reached maximum follow count of root cluster chain, give up");
+
+ vs = volume_id_get_buffer(id, off, 0x200);
+ if (vs == NULL)
+ return -1;
+
+ if (label != NULL && memcmp(label, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, label, 11);
+ volume_id_set_label_string(id, label, 11);
+ } else if (memcmp(vs->type.fat32.label, "NO NAME ", 11) != 0) {
+ volume_id_set_label_raw(id, vs->type.fat32.label, 11);
+ volume_id_set_label_string(id, vs->type.fat32.label, 11);
+ }
+ volume_id_set_uuid(id, vs->type.fat32.serno, UUID_DOS);
+
+ found:
+ volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
+ id->type = "vfat";
+
+ return 0;
+}